Replace certain columns of a matrix with 0?

Let's say I define a 10x10 matrix (call it "A") and want to re-define a new matrix (call it "A4") that is the same as matrix "A" except only the original first 4 columns are kept... and the last 6 columns are replaced with zeros?

Basically, how I get from this:

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

1 2 3 4 5 6 7 8 9 0

to something like this?

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

1 2 3 4 0 0 0 0 0 0

Fairly new to Mathcad here, so thanks any help anyone can give!

Answer 1

[Walter Roberson]

A4 = A;
A4(:,5:end) = 0;

PS: we deal with MATLAB here, not with MathCad.

[Justin Bolinger]

Sorry, I'm a Chemical Engineer by education and we always used MathCAD. I got the names mixed up. Thanks so much for the help!